Sewing machine



April 1, 1952 T. VAN TUYL ETAL 2,590,907

SEWING MACHINE Filed May 25, 1947 13 Sheets-Sheet l Auw April 1, 1952 T. VAN TUYL r-:TAL 2,590,907

- SEWING MACHINE Filed May 23, 1947 15 Sheets-Sheet 5 April 1, 1952 T. VAN TUYL ErAL SEWING MACHINE 15 Sheets-Sheet 4 Filed May 25, 1947 Aziys April 1, 1952 T. VANl TUYL. ETAL SEWING MACHINE 13 Sheets-Sheet 5 Filed May 25, 1947 Apil 1, 1952 T. VAN TUYL ETAL SEWING MACHINE 13 Sheets-Sheet 7 A Filed May 23, 1947 April l, 1952 'r. VAN 'TUYL E'rAx. 2,590,907

SEWING MACHINE Filed May 23, 1947 13 Sheets-Sheet 8 /A/ VEN TOQS. J/zomas Ucz/z Jay! fz'ede/fzb/ @cker/72am A Jigs April 1, 1952 T. VAN TUYL. ETAL 2,590,907

SEWING MACHINE /V VEN TUR?. J/zonzas Url/z Jay] @Y A Wma/#a5 April 1, 1952 T. VAN TUYI. ETAL 2,590,907

' SEWING MACHINE Filed'May 25, 1947 13 Sheets-Shed'I l0 April 1, 1952 T. VAN TUYL ET AL SEWING MACHINE 15 SheeJtS-Sheet l1 Filed May 23, 1947 April 1, 1952 T. VAN TUYL ETAL 2,590,907

SEWING MACHINE Fild May 23, 1947 15 Sheets-Sheet 12 April 1, 1952 T. VAN TUYL ErAL 2,590,907

SEWING MACHINE Filed May 23, 1947 15 Sheets-Sheet 13 YPatented pr. l, 17952 SEWING MACHINE Thomas Van Tuyl and Frederick Ackermann, Chicago, Ill., assignors, by mesne assignments, to` William R. Donaldson, Northport, N. Y.

Application May 23, 1947, Serial No. 749,902

This invention relates to sewing machines.

It is an object of the present invention to provide an improved mechanism for producing chainlike stitches or stitches wherein successive loops are taken from the same thread, or from different threads in a predetermined sequence.

Another object is to provide an improved simplified mechanism by which the length of stitch is conveniently adjustable over a wide range.

Another object is the provision of mechanism by which the stitch sequence is readily variable throughout a wide range of short and long stitch combinations.

Another object is the provision of an improved sewing machine in which stitch length, stitch sequence as between long and short stitches, and the thread or threads going into the stitches are variable either separately or concurrently, even while the machine is running, to obtain improved locking and ornamental effects.

Another object is the provision of an improved work-support and :presser foot combination which renders the length of loop pulled up by the needle for each stitch independent of changes in thickness of `the fabric being sev/ed, as for instance when crossing a seam.

An important feature of the present invention is the provision of tensioning or thread hold-back means for releasably gripping each thread tc pay it out in the required amount for each stitch as the loop is passed through the fabric by the needle and, subsequently, as the fabric is moved past the needle. Ancillary features include means for varying the tension on each thread for operation at diierent sewing conditions and to produce variable stitch combinations.

The desirability of a chain stitch sewing machine which can impart improved locking effects to the line of stitches by making certain of the stitches considerably shorter than others has long been recognized but, previous to the present invention, no one has disclosed a workable, commercially successful sewing machine capable of producing such a line of stitches by automatically varying the fabric feedl independently of the needle bar action. This has been variously suggested as a desirable result by experimenters in the art, and a line of stitches illustrating this improved locking edect has even been shown in an early sewing machine patent issued near the middl-e of the last century, but that patent does not actually disclose a complete mechanism for sewing such a line of stitches; that disclosure is so incomplete, as in many of the early patents, that it does no more than suggest the desirability for such a machine. In this sense, therefore, the

stitches, of varying length, taken from one or more of a plurality of threads. The nearest approach to this has been disclosed in certain foreign patents in which a line of loose, purely ornamental embroidery stitches is shown, taken from different threads in recurring sequence but which are made in an entirely different manner from those of the present invention and, being purely ornamental, do not possess the improved fabric-holding characteristics of the stitches made with the machine described herein.

In certain aspects, as will appear more specifically in the following description, the present invention constitutes an improvement upon the disclosures of Thomas E. Monroe in Patents 2,152,203 issued March 28, 1939, 2,206,484 issued July 2, 1940, and 2,426,636 issued September 2, 1947; in patent applications Serial Nos. 559,579 and 559,580 (now Patents No. 2,497,231 and No. 2,497,232, respectively, issued February 14, 1950) both filed October 20, 1944; and in patent application Serial No. 474,450 led February 1943 (now Patent No. 2,497,230).

Other objects and advantages will be apparent from the following description taken in connection with the drawings in which:

Fig. 1 is an elevational view of a sewing machine embodying the invention in a preferred form and taken looking forwardly or in the direction of fabric advance;

Fig. 2 is a :plan view of Fig. l.

Fig. 3 is an end elevation of Fig. l as seen from the left end;

Fig. 4 is a vertical cross sectional view of a portion of the machine as shown in Fig. 3 illustrating the work-support in raised position;

Fig. 5 is a vertical cross section taken on the line 5--5 of Fig. 1

Fig. 6 is a vertical cross section taken on the line 9-6 of Fig. 5, showing the parts in adjusted position for making a sequence of identical length stitches;

Fig. 6a is a schematic view of the cam member for imparting up and down movement to the feed foot plunger, showing the various operative surfaces thereon;

Fig. 7 is a view similar to Fig. 6 but showing the 3 parts in the adjusted position for making a sequence of alternately long and short stitches;

Fig. 8 is a bottom View of Fig. 5 showing the lower surface of the fixed presser foot;

Fig. 9 is a fragmentary, vertical, cross section taken from the left end of the machine and approximately through the axis of the n-eedle;

Fig. 10 is an enlarged fragmentary View of Fig. 9;

Fig. 10a is a section of Fig. 10, on the line Illa-Illa;

Fig. 11 is an enlarged cross sectional View of Fig. 10 taken along the line l I--I I.

Fig. 11a is a view similar to Fig. 11 showing the looping member in another operative position;

Fig. 12 is an enlarged view, looking in the direction of fabric advance of the machine, with the near half of the base removed to show one view of the thread handling and looping mechanism;

Fig. 13 is a further view of the thread handling i mechanism in the base showing the parts connecting it with the driving means in the top of the machine;

Fig. 14 is a fragmentary plan View of the thread handling mechanism and the resilient work-support in the base;

Fig. 15 is a fragmentary elevational cross section of the gear box showing the relation between the various gears employed as Well as the cam means for driving the thread handling and looping mechanism in the base;

Fig. 16 is a sectional view of Fig. l5 taken along the line |6-|6;

Fig. 17 is a plan view of a portion of the gearing taken along the line Il-l l of Fig. 15;

Fig. 18 is a cross sectional view of Fig. 15 taken along the line l8-l8 showing a portion of the cam selector means for varying the sequence of threads selected;

Fig. 19 is a fragmentary top view of the fabric foot driving and adjusting mechanism;

Fig. 20 is a view similar to Fig. 19 with certain parts cut away to show a clear top view of the rack employed for regulating the stitch length;

Fig. 21 is a view similar to Fig. 20 with a further portion cut away to show a clear top view of the reciprocable tongue which is employed in making a sequence of alternately long and short stitches;

Fig. 22 is a cross sectional view taken through the stitch length selector knob;

Figs. 23 to 28, inclusive, are individual views of the thread selector cams employed in the present invention;

Fig. 29 is a top view of the assembled cam nest consisting of the cams shown in the previous six gures;

Fig. 30 is a greatly enlarged sectional view of the lower end of the needle bar and the needle showing the hooked needle in open position to receive a thread;

Fig. 31 is similar to Fig. 30 but shows the needle in closed position;

Fig. 32 is a side view taken on the line 32--32 of Fig. 3l showing the T-head that controls the opening and closing of the needle;

Fig. 33 is a sectional View taken along the line 33-33 of Fig. 31;

Fig. 34 is a greatly enlarged cross sectional view of Fig. 31 taken on the line 34-34 and showing the relative sizes of the needle and the internal needle pin;

Figs. 35 to 39, inclusive, are enlarged cross sectional views showing the relation of the needle, fabric, and thread handling member in a num- 4 ber of positions illustrating a complete operating cycle for a single stitch;

Figs. 40 and 40a. (and 42 and 42a) are respectively section and plan views showing schematically a single chain stitch such as may be produced from a single thread by the machine of Fig. 1;

Figs. 41 and 41a (and 43 and 43a) are respectively section and plan views showing a double chain stitch producible by the machine in which three successive loops are taken'from one thread for every one taken from the other thread;

Figs. 44 and 44a are respectively section and plan views showing a double chain stitch prov ducible by the machine in which alternate loops are taken from alternate threads;

Figs. 45 and 45a are respectively section and plan views showing a double chain stitch in which two successive loops are taken from one thread and the next two successive loops are taken from another thread, etc.;

Figs. 46 and 46a are respectively section and plan views showing a single chain stitch in which the sequence of stitch length alternates regularly from short to long;

Figs. 47 and 47a shows a double chain stitch in which alternate loops are taken from alternate threads and in which the stitch sequence alternates regularly from short to long;

Figs. 48 and 48a illustrate a double chain stitch similar to that shown in the previous two figures except that three successive loops are taken from one thread for every loop taken from the other;

Figs. 49 and 49a illustrate a double chain stitch in which alternate loops are taken from alternate threads and in which every other loop is shortened by increasing the hold-back tension on the thread feeding the loop to be shortened (Note that the top views, as shown in Figs. 49a and 47a, appear to be identical but, as shown in the sectional views of Figs. 49 and 47, one stitch is made with a constant fabric feed and the other is made with an alternating fabric feed.) and Figs. 50 and 50a'l illustrate another double chain 'i stitch which may be produced in an alternate mannerusing a pair of like threads.

Frame structure Referring now to Figure 1, a machine embodying one form of the present invention is illustrated as generally C-shaped. Referring also to Figs. 2 and 3, a supporting framework includes a pair of upstanding plates 2| and 22 held in parallel relation by spacer tubes 23 and 24 which are mounted by screws 26. Formed sheets 2l and 28, mounted by screws 29 and 3l respectively provide top and bottom walls to partially enclose a space between plates 2 I and 22. The lower leg of the C comprises a base or housing, generally designated 32, for the thread feeding and looping mechanisrn. This housing 32 includes a stationary portion and a removable portion or cover, generally designated 38 and 38, respectively. The stationary portion 39 includes: a relatively heavy plate 33 secured (by means not shown) to plate 2|; upper and lower plates 34 and 36 mounted on plate 33 by screws 34a and 38a; and a block 31 connected between plates 34 and 36 by screws 34h and 36h, the block 31 being spaced a distance below the upper plate by separators 31a (Fig. 12) to provide room for the operation of the thread handling mechanism, as will presently be described. The removable section 38 includes: a top plate- 39, coplanar with plate 34 and providing a horizontal work table therewith;I and a formed, verticalV plate 4| joined by -screws 40 (Fig. 2) to the plate 39. At each side of the housing is a hook member 43 pivoted on bolt 44 and engageable with the latch bolt 46 to normally holdthe removable section 38 in place.

At the upper terminal of the C-shaped frame is a housing, generally designated 41, formed of plates 48, 48a and 49 suitably connected, as by screws (not shown) and mounted on the side of plate 22, enclosing the needle bar and feed foot operating mechanism. Immediately 'above that and to the right (Fig. l) is a gear box 5|, having a removable cover 52 .and containing the gear and cam mechanisms as well as having the external control members for the feed foot and thread handling mechanisms. In the illustrated embodiment the gear box 5| is cast integrally with the side walls 48 and 48a of the housing 41.

Drive 'mechanism ,The power source for the machine is a motor mounted on a bracket member This bracket member has at its top a motor platform section |2 to which the motor base is mounted by screws (not shown). As shown in Fig. 13, the vertical leg I3 of the bracket member extends through the top plate 34 of the base housing and is mounted by screws |4 and angle bracket I5 to the base bottom plate 36. The motor shaft I6 (Fig. 15) is coupled to the worm shaft |1 by a coil-spring-type flexible coupling I8. Shaft |1 is journaled within ball bearings I9 held against end play by plugs |9a and |9b which are screwed into opposed ends of the gear housing.

The main drive shaft 53 (Fig. 5) is journaled within bearings 54 in the gear box Walls 56 and 51 and terminates at one end with the flywheel 58 attached by bolt 59 and at the other end by a driving member 6| held in place by pin 62 and set screw 63. This shaft is driven by worm 64 through worm wheel 66. As best shown in Figs. 5 and 15 the worm wheel 66 includes side bearing plates 61 between which is carried an overrunning clutch, comprising a central clutch member 68 and clutch balls or rollers 69, carried in notches formed in the periphery of the member 68, as shown. The inner surface of the rim of the worm wheel 66 forms a raceway so that, as will be understood, the worm 64 will drive the shaft 53 in one direction (counterclockwise in Fig. but not in the other. By this means manual turning of the main shaft, without turning the worm 64 to back-drive the motor shaft |6, is provided for. Adjacent the worm wheel 66, a collar 1| is fitted on the main driving shaft 53 providing the proper spacing from a pinion 12 which'is driven by shaft 53 and, as will be described subsequently, drives the mechanisms for automatically varying the stitch length and for varying the thread sequence in the stitch succession.

Feed foot drive The feed foot 13 (Fig. 5) is pivotally mounted on pins 14 carried at the bottom of feed foot plunger 16, the latter in turn, being pivotally mounted on a fixed bolt or pin 11 mounted in walls 48 and 48a (Fig. 6). A bracket 18 carried on the feed foot plunger by screws 19 has a pair of transverse extensions 8| with longitudinal slots 82 for` engaging the stationary pin 11 to permit combined reciprocal and pivotal movement of the plunger 16 as will next be described.

The driving member 6| operates both the feed foot plunger 16 and the needle bar 83 simulta- -neously. To this end the member 55| fits within the follower head or yoke 84 formed on the top of the feed foot plunger; and the needle bar 85 (Fig. 12) is formed at its upper end with a section 86 having a horizontal slot 81 within which is slidably engaged the bearing member 88 carried eccentrically on the driving member 6| by pin 89. Sidewise .movement of both the feed foot plunger 16 and the needle bar 83 is restricted .by the snug t of housing walls 48 and 48a (Fig. 6).

For purpose of description herein, the direction of fabric advance will be considered the forward direction of movement; but, in referring to parts of the machine, the front will be considered that shown in Fig. l, which is normally nearest the operator. The back side of the feed foot plunger yoke 84 is formed with av cam surface, generally designated 9|, the portion taken ahead of the cross sectionof Fig. 5 being outlined in broken lines, also shown enlarged in solid lines in Fig. 19. Referring to Figs. 5, 6 and 19, it will be seen that counterclockwise movement (Fig. 6) of the driving pin 62 will cause the end portion 92 thereof to move the yoke 84 as follows: During the first approximately l@ turn, along cam surface 9|a (Fig. 19), the yoke 84 will be moved backward, that is downward, as seen in Fig. 19; during the next approximately quarter-turn, the yoke will be held in this position as the driving pin moves along the fiat portion Bib of the cam surface; during the next approximately 1/8 turn, as the pin moves along the descending cam surface 9|c, the yoke will be moved forward (upward in Fig. 19) under the urgence of spring 93 (Fig. 3) which is carried .by pins 94 and 96 fastened respectively to the yoke and the gear housing 5|; and the next half turn, to complete one revolution of the pin, will be with the latter moving along the low, flat portion Bld of the yoke cam surface. In other words, since the feed foot plunger 16 is pivoted on pin 11, as above described, movement of the feed foot 13 itself will be first backward, then forward.` This is only part, however, of a compound motion which also includes an up and down movement, now to be described.

As shown in Fig. 6a. the rotatable driving member 6| is formed with opposed high and low surfaces constituting dwell portions W and X which occupy approximately 90 each and which are separated by feed-foot depressing and elevating portions Y and Z, each occupying about 90. The spring 91, (Fig. 6) seated in the cup 98 of bracket 99 which is mounted on the gear box by screw |9|, bears upward against the underside of the feed foot yoke 84, around the extension |62, and urges the cam follower portion |83 of the yoke upward to follow the cam surface W-Z-X-Y as the driving member 6| rotates.

It will be apparent from the above that, for each counterclockwise revolution of the main drive shaft 53 from the Fig. 6 position, the feed foot 13 will be moved through the following cycle at successive approximately quarter turns: (1) forward, that is in the fabric feeding direction; (2) upward; (3) rearward, that is oppositev to the fabric feeding direction; and (4) downward.

Regulation of stitch length The'length of stitch is regulated by providing means for limiting the stroke of the feed foot to thereby limit the amount of fabric moved per stitch. In the present instance this is carried out by regulating the forward (that is to the left,

Fig. 5) movement of the feed foot yoke 84 by the construction now to be described. Along the outside of the gear box a pair of horizontal spaced parallel rails |04 are formed, as for instance by casting integral with the gear box and they provide therebetween a slideway |06 for the U-cross-section rack |01. The upper section of the U, as best shown in Fig. 20, is formed with an outwardly rising inclined surface |08 which the feed foot plunger extension |09 strikes to limit its forward movement under the urgence of spring 93. Thus, the position of rack |01 along the slideway |06 is determinative of the extent of stroke of the feed foot by limiting the forward movement of the extension |09. As will be apparent on examining Fig. 20, moving the rack |01 to the right shortens the stroke o f the feed foot and hence the spacing between stitches; and moving it to the left lengthens the stroke to a maximum which is reached when,as in Fig. 19, the extension |09 is aligned with the flat low surface on the rack. A spring |00, connected to the rack |01 and to the cover 52, urges the rack to the left to maintain it snugly pressed against the pinion I3.

As best shown in Figs. 6 and 22, the rack teeth |2 are meshed with the pinion I3 for selectively positioning the rack along its slideway. The pinion H3 is carried by shaft ||4 within bushing I6 mounted on the bracket ||1 which overlies the rack and pinion mechanism. A tubular collar |0 is attached to the bushing ||6 by a set screw ||9 and has a flanged forward end portion 2|. At the end of shaft ||4 is the stitch length adjusting knob |22 mounted by set screw |23. Within the recess |24 in the knob is a coiled spring |26 adapted to press the detent |21 into yieldable engagement with any one of a number of detent recesses |28 in the flange |2| to maintain the knob |22 (and hence the rack |01) in a selected position to call for a particular length of stitch.

From the foregoing it will be apparent that counterclockwise movement of the stitch length selecting knob |22 will cause a shorter stitch to be formed and vice versa.

Sequential variation of stitch length Variation of certain stitch lengths in a series of stitches is effected by limiting the stroke of the fabric foot in varying amounts along the series of stitches and correlating the amount or length of thread in each stitch to the length of stroke of the fabric foot. A simple form of the invention is illustrated here, for making a series of alternately long and short stitches. In this case, the long stitch is determined by the feed foot extension |09. striking the rack |01 in any adjusted position and additional means, including the sliding tongue |29 (Fig. 21) is provided for limiting the alternate, short strokes to a value less than that. Referring to this part of the mechanism more specifically, the rack |01 is formed with a groove |3| (Fig. 22) for the slidable tongue |29. The tongue is provided with a stop surface |32 and is operable to intercept the yoke extension |09 every time a short stitch is made, this being, in the illustrated embodiment, every other forward movement of the yoke extension |09. Fig. 21 illustrates the interception of the extension in this manner for a short stitch.

Means for automatically driving the tongue |29 to intercept the extension |09 at every other stroke is shown in Figs. 6, 7, and 17. A gear |33 is mounted on shaft |34 which is journaled in the Walls of the gear box 5|. Gear |33-is meshed with pinion 12 on the main drive shaft; their ratio is 2 to 1 so the stitch alternating shaft |34 rotates at exactly half the speed of the main driving shaft 53. The alternating shaft |34 carries at its outer end the cam member |36 which has low and high portions |31 and |38, respectively, each extending approximately halfway around the cam, the high portion engageable with the transverse extension |39 of lever |4| to maintain the latter pivoted to the right around the pin |42 as shown in Fig. 6. The lever |4| is provided with an upper, open slot |43 for pivotally engaging the transverse extension |44 of the tongue |29 to move it back and forth in the rack groove |3I. Since the alternator shaft |34 rotates at just half the speed of the main driving shaft 53, when a long stitch is made, the tongue |29 will be held clear, to the right, by cam |35, as shown in Fig. 6 whereby the feed foot extension |09 will be free to move a maximum stroke all the way forward to the rack surface Il, as shown in Fig. 19, to make a long stitch, the latter being controllable as to length by moving the lower portion of rack inclined surface |08 into alignment with extension |09 as shown in Fig. 20. And when the next stitch is made. the cam |36 will permit the tongue |29 to be drawn to the left by spring |46 which is attached to the pin |41 mounted on the gear box wall; this will place the stop surface |32 of the sliding tongue in the position of Fig. 21 to limit movement of the feed foot extension to make a short stitch.

The stitch alternating tongue |29 may be used or not, as desired, by means of a hold-away cam |48 (Figs. 6, '1, and 22) connected by shaft |49 to indicating knob |5|. When the hold-away cam is in the position of Fig. 6, the tongue |29 will be held to the right, as shown in Fig. 19, free o'f the alternator cam |30, to permit the sewing of a series of identical stitches of a length determined by the position of the rack inclined surface |68; and when in the position of Fig. 7, the tongue will be reciprocated, by alternator cam |36 and spring |46, between the Fig. 19 and Fig. 21 positions to permit the formation of a series of stitches of alternate lengths.

Fabric foot and work support construction A fixed fabric foot, or presser foot |52 (Figs. 5 and 8) is held by thumb screw |53 on the bottom of the downwardly extending stationary member |54 which in turn is mounted between plates 48 and 48a by screws |56.

A resilient work-support |51 (Fig. 9) is adapted to press the fabric being sewed yieldably upward against the undersurface of the foot |32. It is an inverted, substantially cup-shaped member, apertured at |58 for the needle, The member 51 is mounted as by welding on the end of a vertical rod |59 reciprocably journaled within bores |6| and |5|a in the block 31 within the base. The block 31 is cut away at |62 for a block |63 positioned on rod |59 by set-screw |64. A stud |66, carried by block |63 coacts withl certain other parts to depress the work support |51 as will be described. The block 31 is also cut away at |61'for the end of the L-shaped leaf spring |63 which bears upward against the bottom of rod |59 to normally urge the worksupport |51 upward toward the fixed foot. As shown in Fig. 13, the leaf spring |68 is fulcrumed atop a'convex block |69 and at its end remote from the rod |59 is fastened to the base plate 36 by screw I1I and thumb nut |12 which may be turned one way or the other to adjust the upward force on the work-support lift rod |59.

Figures 9, 13 and 14 show also the mechanism employed in the illustrated embodiment of the invention for depressing the work-support (as illustrated in Fig. 3) while fabric is being inserted kor readjusted beneath the needle. This depressing mechanism includes the manually operable lever |13 fulcrumed on bolt |14 mounted on plate I3; the intermediate member or link |16 pivoted to the lever |13 at |11; and the operating lever |18 fulcrumed on block 31 at |19 and pivoted to the link |15 at IBI. The lever |19 has a horizontal portion |82 (Figs. 9 and 13) which extends to the right, beyond the connection IBI with the link, and counterclockwise rotation of the lever |19 from the Fig. 13 position to the Fig. l position will thus move the portion |82 of operating lever |18 down upon the stud |56 to lower the work-support |51 against the upward force exerted by the leaf spring I 58. The lever will be held in this position due to the fact that the fulcrum point I 11 is moved overcenter past a line through pivots |14 and |8|.

Thread handling and looping mechanism Thread is fed to the needle below the worksupport |51 by a thread feeder or distributing member |83 (Fig. 10) and associated mechanism. As shown in Fig. 12, spindles |84 and |84a for a pair of spools |86 and |86a are supported on the base plate 36. The threads are passed through suitable thread guiding and tensioning means including conventional tensioning devices |81 and |9111 by which the tensions on the threads are separately variable by adjusting knobs |99. From the tensioning devices the threads pass through the eyelets |89 and |89a (Fig. 11) in the distributing member to be picked up by the needle as will be described.

The distributing member |83 (Figs. 10 and 13) is formed at its upper end with a recessed surface I9| flanked by the pair of eyelet members |89 and |89a and also flanked by cam surfaces 209. It is substantially vertical except for the offset horizontal section |92. The lower portion is substantially rectangular, having the side members |93 connected by the upper portion |94 r and the lower portion |96. At each side, above the bottom member |99, the distributing member is hinged to a pin |91 carried by the ears |99 struck forwardly from the reciprocable operating member |99 which is movable from side to side to cause the needle to pick a thread from either of the spools |89 or Ia as desired. One end of the member |99 is formed with a slot 29| engaging the pin 292 fastened to the supporting block 31. A bracket 203, likewise mounted on the block 31, overlies the operating member |99 and maintains it in closely guided relation with the other parts. At its opposite end, the operating member |99 is pivoted to an arm of a bell crank lever 294 mounted on plate I3, the bell tra' This counterclockwise movement is limited by engagement of the distributing member with the front surface of the operating member |99 also as shown in Fig. 10. Thus it will be apparent that the distributing member |83 is independently, pivotally movable with respect to the operating member |99. This provides for the backward movement of the eyelets |89 and |89a from the path of the needle, as shown in Fig. 11a to clear the needle and to press a thread against the latter as it is moved therepast by the operating member |99. Cam means, including the pair of convex surfaces 209, (Figs. 10a, 1l, 11a) on the distributing member and the concave surface 2I| in the block 31, is effective to back the eyelets |89-I89a clear of the needle (as shown in Fig. 11a) when the operating member |99 is moved in either direction from the center position illustrated in Fig. 11.

Needle bar and needle construction At this point, before proceeding further in the description of the thread handling mechanism, it is believed that it would be helpful to describe the parts of the needle bar construction not already referred to, as well as the details of the needle itself.

Referring first to Fig. 5, it will be seen that the needle bar 83 is maintained snugly guided along the front wall plate 49 by means of back guide plates ZIIl and 2IDa which are supported on the side walls 48-49a. The lower portion of the needle bar and the needle are best shown in the enlarged views of Figs. 30 and 31. The needlebar carries a hooked needle 2|2 in a slot 2|3 at its lower end, the needlebeing fastened therein as by means of a transversely-bored retaining bolt 2I4 and a locknut 2 I6.

Cooperating with the hooked needle 2|2 is a needle pin 2 I 1 more fully described below having a T-head 2|8 which is accommodated by a cutout 2 I 9 in the needlebar. The needle pin 2 I1 is preferably formed of spring steel or other resilient maiirial and the portions adjacent the T-head 2|8 bowed as shown to bias the latter to the right (Figs. 30 and 31) to be readily engaged within the detent recesses 22| and 222 formed on the interior surface of the housing wall plate 48a adjacent the upper part of groove 2|3 in the needle bar. By means of this mechanism, the needle pin will be held back by the T-head 2|8 engaging in the upper detent 22| (see broken line view in Fig. 31) as the needle begins to descend from the uppermost limit of its travel. This permits the needle bar to move the needle 2I2 downward independently of the needle pin 2|1, as the cutout 2|9 is moved past the T-head, thereby causing the needle hook to be opened, as shown in Fig. 35, to eject the previously pulled up loop as it penetrates the fabric. 'At the bottom limit of the needle stroke, the T-head 2I8 will be seated within the lower detent recess 222, as shown in Fig. 30, to hold the barb open during the beginning of the upward stroke long enough for the distributing member |83 to wipe a thread into it. Subsequently, `as the bottom shoulder of the cut-out I9 strikes the T-head 2 I8, as shown in Fig. 3l, the barb will be closed during the remainder of the upward stroke as a new loop is pulled through the fabric.

An important part of the present invention resides in the means for retracting the end of pin 2 1 on the downstroke to keep it from catching in the fabric and for movingA the pin outward to cover the end of the barb and keep it from catching in the fabric when it is moved upward.

The needle groove 22| for the pin 2|.1 is formed. at its lower end with an out-turned shoulder 22.2 for guiding the end of the pin outward over the barb 223 in the Fig. 3l position; and, the lower end portion of the pin 2 I1 is biased toward the interior of the groove 22| so that, as shown in Fig. 30, it will be retracted therewithin when the hook is open.

Thread handling drz'oe mechanism The mechanism for driving the thread handling mechanism for causing the distributing member |83 to present selected threads to the needle in a selected sequence is best shown in Figs. 15 to 18 inclusive and Figs. 23 to 29 inclusive. The alternator shaft |34 carries a pinion 224 held in place by collar 226. This pinion is meshed with gear 221, twice its size, that is rotatably journaled on the stationary shaft 228 supported `by the gear box walls. A spacing collar 229 maintains gear 221 out in line with pinion 224. Since, as previously described, the alternator shaft |34 rotates at half the rate of the main drive shaft 53, then the gear 221 must rotate at one-fourth the rate of shaft 53. Rotatable with, and driven by gear 221 is a nest, generally designated 23|, of cams which are individually designated A, B, C, D, E, and F, separated from one another by annular discs 232. The cams, as well as the separator discs are assembled as a single rotary unit with the gear 221 by ineans of pins 233 extending through bored holes 234 in these members.

A cam follower 236 (Figs. 15 and 18) is slidably mounted on the square portion 231 of shaft 238 which is pivotally journaled in bearings 239 in the gear box The exterior end portion of the shaft 238 is carried by bracket 24| mounted by screw 242 to the front gear box wall. Spaced therefrom by the tubular member 243 and mounted by screw 244Aon the square shank 245 is a lever 246. Thus, it will be apparent that the cam follower 236, the shaft 238 and the external lever 246 comprise a concurrently pivotable sub-assembly. As bestr shown in Fig. l, the lever 246 is connected by rod 266 to operate the bell crank 264 which drives the thread handling mechanism in the base housing. A coil spring 241 connected to the bell crank 264 and to the bracket 248 screwed to p-late I3 is effective to urge the lever 246 and, hence, the cam follower 236 in a clockwise direction to press the latter against the periphery of the particular cam desired thereby causing it to follow the contour thereof.

Means for selecting the particular cam that the member 2 36 is to follow is best shown in Figs. l5, 16, and 11. It will be seen that this means must operate first to lift the follower clear of the separator discs 232, and then translate the follower along the shaft 231 to the desired position. A selector shaft 249 having a circular section 25| journaled in vbearings 250 in the gear box and a square section 252 extending forwardly therefrom has a member 253, with a helical groove 254, mounted thereon by set screw 256. Seated in the helical groove and slidable therein is the tail section 251 of the follower 236. It will thus be apparent that rotation of the helix member 253 will be effective to move the follower along its shaft 231, providing of course that the follower is first pivoted to clear the separators 232 (by means yet to be described). On the exterior portion 252 of the selector shaft 249 is a control knob 258` and a detent disc 259, both being reciprocably but not rotatably mounted with respect to the shaft itself, the knob being held normally outward against the head of screw 26| by coil spring 262. The tail end 263 of the lever 246 is positioned to be engageable by the forward fru'sto-conical surface 264 of the knob 258 so that, as shown in Figs. l5, 16, and 1'1, for ward movement of the knob 258 will thrust the lever tail 263 aside sufficiently to pivot the follower 236 counterclockwise (Fig. 15) sufficiently to clear the separators 232, whence the follower may be moved to a selected cam simply by rotating the knob 258 in one direction or the other. The detent disc 255` is formed with a series of peripheral recesses 266 which are engageable with the spring-pressed detent 261 in each posi tion at which the follower 236 is in substantial alignment with one of the cams A-F.

Summarizing the foregoing, the cam-changing operation will be effected in the following manner. Assuming that the follower is initially in the position shown in Fig. 1'1, engaged with cam F, which, as will be seen, will make a series of stitches in which two stitches are selected from the left hand spool |86a and the next two from the right hand spool |86, etc. To change to cam A, which will cause all the stitches to be taken `from the right hand spool, as will also be described subsequently, it is necessary only to press the selector knob 258 inward to displace the lever tail portion 263, then turn the knob clockwise until the R" (Fig. 12) on the selector knob face is aligned with a suitable index point (not shown). An important feature of this part of the invention resides in the fact that this adjustment, as with all the other adjustments relating to the stitch length, stitch sequence, and thread selection, may readily be carried out while the machine is in operation. It will therefore be possible to progress through almost imperceptible intermediate combinations, from thread of one physical characteristic to thread of another.

Referring now to the details of the thread selecting cams themselves, shown in Figs. 23 to 28, inclusive, it will be seen that at each quadrant of each cam is a surface I of intermediate height corresponding with a central position of the thread distributing member, as illustrated in Fig. 36. Between some succeeding intermediate surfaces I are high level surfaces indicated L (effective to cause a loop to be taken from the left thread L) and between others are low level Surfaces indicated R' (effective to cause a loop to be taken from the right thread R) As will be seen by inspection of Figs. 13 and 15, the high cam surfaces L will move the slide |99 and distributing member |83 to its right hand limit (Fig. 38) whence a loop of thread will be taken from the left hand spool; and conversely the low cam surfaces R will pemit the slide |99 and distributing member |83 to be moved by spring 241 to its left hand limit whence a loop of thread will be taken from the right hand spool. Referring now to the cams as they are shown in Figs. 23 to 28. it will be seen that the individual cams will cause thread to be taken from the right or left hand spools in the following order depending on the cam used:

Cam A-All threads from the left spool (see Figs. 40 and 40a).

' Cam B-Left, right, right, right (see Figs. 4l and 41a).

Cam C-All threads from the right spool (see Figs. 42 and 42a).

Description of a thread handling cycle A complete cycle for making a single stitch is shown in Figs. 35 to 39 inclusive. In explaining this cycle, consider the cam means 23| as set with follower 236 engaged lwith cam E' so that successive stitches are made from alternate threads L and R which are taken respectively from spools |86a and |86. For clarity in the drawings, threads L and R are illustrated as black and white, respectively.

Starting in the position of Figure 5 which represents the parts in their positions when the needle bar is at the top of its stroke and the feed foot plunger is at the bottom of its stroke, the rotation of the main shaft 53 through a full revolution completes a cycle of stitching operations of the feed foot plunger 16 and needle bar 83, but pinion 224 (Fig. 17) produces only a quarter revolution of cam E so that during the stitching operation shown in Figs. 35 to 39 the follower 236 passes from a low level to a middle level and then to a high level. (Alternate stitching cycles would be just the reverse, that is from high, through intermediate, to low to take a loop from the other thread, when cam E is used as assumed.)

Assume further that, in Fig. 35, the needle is descending from its uppermost position after drawing up a loop from thread R; the needle pin 2|'l is beginning to open the hook so as to release the loop while piercing the fabric to make the next loop.

Fig. 36 shows the needle, with its hook fully opened at the lowerxnost limit of its stroke and with the distributing member |83 centrally positioned due to the follower 236 riding on an intermediate surface I'of the cam at this time. The threads will be held taut by their respective tensioning devices and it will be seen that moving the distributing member quickly to the right or left while the needle is in substantially the Fig. 36 position will wrap one or the other threads around the needle and as the needle is moved upwardly the thread will be trapped in the open hook.

Fig. 37 shows a succeeding step after the distributing member is moved quickly to the right due to the follower 236 riding up onto a high level surface L'. Figure 37 also illustrates the position where the needle has risen sufhciently for the pin 2|`| to close the hook and trap the thread and to cover the barb as it is pulled up through the fabric.

Fig. 38 shows the needle about to draw the thread up through the fabric and also shows the right hand limit of movement of the distributing member. Furthermore, it illustrates the function of another feature of the present invention Y which takes the form of the plate 268 having the thread guiding aperture 269. This aperture ispreferably rounded at the edges as shown to present a smooth surface to the thread passing across it. As shown in Figs. 37 to 38, it functions to limit the angle of approach of the thread to the aperture |56 of the work support; if this angle is too sharp it will cause an undue amount of friction between the thread and the worksupport thereby interfering with the proper operation of the device and in some cases even causing breakage of the thread.

Fig. 39 completes the cycle of operation, showing the needle beginning to descend after drawing up a loop from thread L and showing the distributing member beginning to move leftwise due to the cam follower beginning to move down to a cam surface I of intermediate height.

In connection with the detailed description, just above, of the needle and thread handling mechanism, it is believed that at this point it would be desirable to summarize the coaction between the feed foot and the needle bar so that a clear picture may be had of the operation of all the working elements including the needle,

the feed foot, and the thread handling mecha- V nlsm.

It has already been observed that the cam surface on driving member 6| is divided into high and low dwell portions W and X respectively and descending and ascending surfaces Z and Y respectively, as shown in Fig. 6a; and furthermore, that each of these surfaces is effective on the feed foot plunger for approximately degrees of main driveshaft rotation. And, as already stated, the division of rotary movements into quarters is not exact and need not be so, but a discussion in round figures of the relation of the feed foot and needle bar movements and omitting small angular variations will serve to simplify the saine.y Starting in the position of Figures 5- and 6, a complete cycle of movement may be analyzed in successive steps of one-fourth of a revolution, as set forth in the following table:

Action of Feed-Foot 73 Action of Needle-l3ar 83 First Moves to the left (Fig) to Moves down, T-head 21S fourth. feed fabric past the needle retained momentarily in and draws loop out over recess 221, opens the needle fabric eouivalcnt to dishook to release the pre tance between successive viously formed loop just needle penetrations. beforeneedlecntersfabric. 'This movement is completed just before the needle strikes the fabric.

Second Moves up Moves to bottom limit with fourth. needle eve still open and thread distributing member 183 in center position as shown in Fig. 36.

Third Moves to the right, Fig. 5, Moves up to halfway posifourth. opposite to the fabric tion as shown in Fig. 38, feeding direction. with needle eye closed on one of the threads.

Fourth Moves down, returning to Moves to upper limit, to fourth. the Fig. 5 position. the Fig. 5 position. lhis is substantially the same as shoxm enlarged in Fig. 39 except that the needle eye is closed on the newly drawn up loop.

Stitch. combinations Figs. 40 to 59a, inclusive, illustrate certain of the wide variety of stitch combinations which are possible with this machine.

In Figs. 40 to 45d, the stitches are all the same length and illustrate how the succession of stitches may be varied to include different threads in different sequences depending on which of the cams A, B, C, D, E and F (Figs. 17

51ans 29) is utilized. 

